First let me say that the game has a lot of depth and character. Anyone who reads this and hasn't voted for steam green light and/or supported the alpha on Desura please do so!
Some suggestions, I'm sure several of these are already being considered but here ya go:
1) We definitely need a run option while out of combat - a shift click for run and 'always run' option would be ideal. This gem of a game will get roasted for this by reviewers if not implemented.
2) A map easing navigation and pointing out North, South, etc would save a lot of guess work. Sure you can see a total area that you have discovered when you are in a section you have already been in, but when trying to navigate the cave system it becomes easy to go in the wrong direction. For instance, I went left instead of right coming out of the caves for the first mission and was way off track for a good hour. Exploring is great but again I feel that professional reviewers will find fault with the lack of map.
3) As for PSI points regeneration...maybe the player could craft items/devices with varying degrees of passive psy replenishment. A player with high skills could craft a high end device if they invest in the skills and find the necessary parts. Lesser devices could be crafted as well with weaker regeneration capabilities. This would encourage players to really invest in PSI skills without constantly shelling out money, yet still making it a resource to be managed. The crafted device could run on purple mushrooms. Perhaps the player could even craft a mushroom growing device or something.
4) Crossbow bolts should have a chance for recovery off the corpse of a slain foe. I'm thinking of 'The Walking dead' series here where one of the characters uses a crossbow and recovers bolts when possible. One of the advantages of such a weapon is that you can recover ammunition for it. It doesn't have to be 100% recovery, some will get bent or broken, etc...but it seems kind of silly that bolts just disappear. If I were in an environment where ammo was sparse, the crossbow would be a go to weapon for this very reason.
I'm not sure if psy mushrooms grow back over time but I think they should...fungus typically grows pretty quickly and it would add to the realism and make psy more viable...If you can plant spores or they grow back it would kind of be like Pokemon games where you planted berries. I will add more later, but just know that I wouldn't waste my time offering suggestions unless I thought that you have a chance to make something special here...and you definitely do! Keep up the great work!