I really think it is not enough time to make a game.  I know you can do something  I have done before ("https://xentios.itch.io/alone") but even this simple game with ready to use assets from asset store took near 3 hours to do from scratch to publish.

I just don't see the value in limiting time this much. Why not go traditional 2 days if we want quick results?  

I have made many games in three hours, I have often participate here in some trijams. The problem is, that here are many fakers and cheaters, which are making not their game in 3 hours, they spend 10 hours or more. The trijam should not go three days, it should go only three hours!

The 3 hours is more like a timer as the jam interpreted--with only development time counted(Obviously participants can still go overtime and log their time as overtime). Therefore, it is purely on the participators to pause and start the timer again and be honest with their time. In fact, the 3 hour timer isn't as big of a difference for me than 2 days, for I only get about 5-6 hours to allocate to my game creation in 2 days.

The time aspect of this jam is a fun challenge I try to keep up--sometimes I make a good game, sometimes--not so good. Most game in this jam are more of simple prototypes, just like an idea to test on for future development.

I think every Jam has to be different in some ways, and this is the way Trijam is interesting. 

Treat it like a 3hr window to prototype one mechanic. That's already a win in my view

I made gun 4 dead in 3 hours which I did for a different game jam

couple trijams ago or so

Another thing to keep in mind is that the rules state that the 3 hours is only for "coding, making sound effects/music, art, and other assets. Writing a design doc, coming up with ideas, compiling your game, or making the itch.io page for it does not!"

Based on this, things that I have not counted as part of my 3 hours before are:

• Watching YouTube videos to learn new technology (recently been getting in to Shader Graph on Unity)
• Creating a prototype using that new technology while watching videos
• Messing about with different ideas in my prototype, e.g. shader settings, or particle effect settings
• Brainstorming with team mates on Discord, including creating sketches in MS Paint or with paper and pencil
• Writing a design doc - Sketching out level designs on a piece of paper

With my prototype I typically end up with some kind of horrible spaghetti code which I then discard. However, a prototype allows me to solidify the nebulous ideas I have, meaning that when I get started with my 3 hours I know exactly what I'm going to make.

I also completely agree with I_AM_STUPID above that I don't often get lots of free time at weekends, so having a limit of a few hours is really helpful. I've done a couple of jams that were all weekend before (e.g. Mini Jame Gam #41) which can be fun, but equally my wife and kids tend to get significantly less attention when I do that...