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Rocket Jump Technology

A member registered Feb 16, 2017 · View creator page →

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Slightly longer than expected (a lot of issues to fix!) there's now Pre-alpha 7.1 which shouldn't have problems with doors anymore. The save would be very useful in the future yes, although this time the error log was all that was required. Thanks!

That's super useful thanks Adrellias! Does this happen every time? Looking at the stack trace I'm assuming it's when you have some furniture placed? The actual crash is because there's some furniture being saved which doesn't have a furniture type (i.e. if it is a workbench, table, chair, etc.) which shouldn't be possible but clearly something is going wrong. Oh actually it's a doorway and this had made me realise I've not been testing doors and saving as hard as I should, clearly there's a bug there. Thanks to this I should have a fix out today!

That's absolutely all going to be in the game as it's developed further! This really is a pre-alpha prototype to show the direction the game's going in, and not intended as a full set of content yet. The next update will include save files which will automatically be available across different versions and the rest isn't too far off. That said, this is probably the end of life of the free version (though I may end up putting up the save and load-enabled version) as the game will be transitioning to a paid release in early 2019 (to be available on, if you're interested you can pre-order it at

Hmm that helps (sorry for the delay), it *could* be an issue with only having 3gb of ram as the game can get to using that much, but more likely it's due to the spec of the on-board GPU. While it's certainly powerful enough to run the game it seems there's a bug in the graphics shader running on that hardware, so I'll have to see if I can get my hands on a similar machine to look at it further. Same goes for supporting win32 properly really.

That's one crazy looking bug! I've not heard of this happening before so without more details I won't be able to recreate it and fix it. Please could I ask for the following information from you?

  • Operating system? Are you on a 32 or 64 bit version?
  • How much RAM/memory do you have?
  • What graphics card do you have?
  • What screen resolution are you using?
  • Perhaps most importantly, which build/version of the game is this?

There isn't a way yet but that's what I'm working on right now! That said, what's out already is probably the last free update, and saving will be in the paid alpha available from

Okay, sorry to hear that, I think there's no option but to launch the game from command prompt (rather than just clicking the .exe in windows) and seeing what output that spits out to explain what error it is you're getting.

Right the new build is out now, you can edit settings.json in the main folder with a text editor (Notepad++ recommended) to hopefully start the game windowed and/or in a different resolution

Right the new build is out now, you can edit settings.json in the main folder with a text editor (Notepad++ recommended) to hopefully start the game windowed and/or in a different resolution

Alright, sorry to hear that (and thanks for your patience), I'm working on this launcher options thing now so I'll give you a nudge when it's up for you to try it out :)

There's lots of features which are going to distinguish the game as it's own thing, but right now it's still a very early pre-alpha so while I get the basic systems in place it's not really going to have the opportunity to show that uniqueness off until it's more developed.

Hiya, could you let me know what OS, graphics card and memory your machine has? Also what desktop resolution you're currently set to as it tries to launch initially in full screen at the desktop's resolution, which some people seem to be having issues with (as it needs to create several full screen frame buffers). If you do have a large resolution, it's worth turning it down a bit to see if that is the problem or not.

Is there anything in the log.txt file?

I'm currently working on adding some launcher options so you can configure how it launches the game before it fails.

Okay, if you have a java 8 runtime you should be able to launch the game from the command line (in the directory) with `java -jar undermount-desktop.jar` and definitely get some output that way. Sorry you're having issues.

There should (hopefully) be something in the log.txt file next to the game, please could you paste the contents of that here?

It'll (only) work if it's between two walls that are a tile apart. Needs improving to make things easier :)

Ah, yep that is a bit of an issue right now as you can't build bridges yet, though that's a feature that'll be in the next major release, so I don't plan to "fix" it right now.

Just a bit wary of putting out the 32bit version to everyone when I can't test it myself yet, and not sure that it'll work on some hardware, I need to do some testing with lower end hardware but it looks good that I'll be able to support it properly :)

Sorry should have put the below as a reply to you :)

Here you go, hope it works for you!

Without a machine to test it on I don't think I can commit to releasing a 32-bit version, there's something of a chance it won't work well enough and I don't want to put that out publicly while not knowing. I'll see about putting up a "secret" 32-bit version somewhere.

Thank you very much! There actually is already a Patreon at as a sort of build up to the Kickstarter over the last few months (patreon backers will be credited in the post-campaign pledge manager equal to what they put in), so now the Kickstarter is in full swing (and certain to reach the goal!) I guess it will transition to more of a donation thing as there's a few crazy people who want to keep that going :)

Hi, thanks for the post! Always nice to hear of suggestions

#3 and #4 are definitely in the pipeline for the future, #2 I'm not sure about, I think I'd rather have an in-game tutorial.

#1 Probably won't happen, the art style is what it is and it'd be far too costly to completely change now. That said, it'll be open to mods in the not too distant future if someone wants to replace the default graphics :)

That's probably the highest praise I've ever received for this game (or anything really) so thank you very much!! It's still very early and I have a lot of very exciting things I can't wait to add in the future :)

Just to say I'm still looking at this. Very interesting that it started logging with a different error without any real change. Essentially there's some error in creating a frame buffer of that size in RBGA8888 format, though it really should be supported. 

I've put up a new build now which attempts to fall back to a 1920x1080 resolution in case provisioning the desktop default fails. Ideally I'd have some sort of config app or at least settings file to let people specify this. 

Also added a new build now, though I don't expect it'll help with this problem, but you never know!

Oh also it would help to know what desktop resolution you're set to.

Oh in your original post I thought you were saying it loaded the main menu (where toggle full screen is), but then starting a new game crashed. Hmm so maybe there's something missing in the startup to log any errors, although it's going to have to be a really early point as most of the startup code is covered by logging.

The best thing you could try, if you don't mind, is downloading a Java 8 runtime from then going to the location of the game and executing "java -jar undermount-desktop.jar" which would then definitely spit out some clue as to why it's not working. 

Also might be worth toggling to windowed mode and seeing if that works or not.

Huh, tricky, that's the same graphics card I'm using too. I'm going to fix some other crashes I've been made aware of today and push a new build out, see if I can do more to get stuff into the log for this, can't figure out yet why it would be empty.

Huh, very odd that the log file would be empty and that makes it tricky to track down. Could you let me know what graphics card you're using? Also I've put out a few small bug fixes (though none that I think would make a difference to this) so could you confirm you're on the pre-alpha 6.4 version? Thanks for your patience! 

Good advice!

This was written in Java with the LibGDX framework, as I'm fairly experienced in Java. If you're just starting out, I think I'd recommend GameMaker Studio as an engine to look at.

Everything is via the menu options in the bottom left. Rooms or zones are dragged out with a click and drag action. I don't think building walls is in this (quite old) build, but look out for a massively updated version in about a week!

Hah, sorry, I'll tone it down for future builds, and there'll definitely be a settings menu in alpha 1 to let you control it yourself!

Thanks! Big free update coming in a couple of months to co-incide with a new Kickstarter campaign :D

Thanks, and yes it's using the same art style as Prison Architect and Rimworld. Definite plans for meeting and social areas to keep your settlers near to the base, and the latest updates do have more building options but this isn't publicly available yet - will be updated in July!

There's links to the game's website on the itch page - with the dev updates at

There's a FB page at and Twitter at for more frequent updates

Saving and loading games will be in the next proper update, which work is just about kicking off on! Best way to keep up to date is by signing up the newsletter at

32-bit version is on the page now :)

Thank you, all those things are planned in - this is the very first playable prototype for people to see what we're working on rather than any sort of "working" game at this point. The UI should be completely reworked at some point too :)