I think there is actually only one real light: the sun. All others are those fake lights attached to bullets that I wrote about on Discord and in the devlog. Yesterday I tested an improvement to that fake light idea since overlapping lights get so super bright. My new alternative doesn't anymore but is a bit too weak, maybe that can be improved further with harder rendering tricks.
Yeah a lot of enemies at once are difficult. The idea is to only fight with a few at once avoiding drawing more and more into the fight. They will alert nearby aliens when hit and can of course see you. You can also tactically leave health drops for later if they would overfill you at the moment. You can also get behind obstacles like radar towers, ships and the plant barriers to make them loose sight of you.
With the cooldowns of the weapons (1-2 seconds) there is a certain rhythm of dodging (with space) and shooting you can get into to dodge most bullets. Depending on the rhythm of the enemy shots and amount of enemies that might not work that well. I try to make a video of a more or less full playthrough later and post it on Discord as well.
The controller hint is a missed leftover from when I still wanted to add controller support but I never implemented aiming with that marker so I took most buttons out again and remapped the alt buttons to 1-3. Control remapping and proper settings in general would have been nice as well as a bunch of other things. The current settings have various issues. Can't you just enable an English keyboard layout to avoid that common Azerty issue? German here who has that issue to a lesser extend as well.
I'm working on a lot of things right now like a better vegetation renderer to use in future jams. That did eat quite some time. I wrote down so many things to work on... Including settings. Another big time eater was Amplify Shader Editor failing me and me having to redo some things, I could have avoided that by simply changing the shader model to <=3.5 instead of the standard of 4.5 which doesn't work on WebGL... Found that out after the jam.