Dude, condolences about your artist. That really really sucks and I think you did an amazing job all things considered. Mad respect to you for not giving up and pressing on to finish the jam.
The idea seemed really neat to me! I think the main thing the game could use, perhaps in a post jam update, is a bit of a learning curve. The commander introduces the time mechanic, the motion mechanic, and the shrine mechanic all at once, which makes it difficult for the player to understand what each of those things does, and the buttons for it. Further more, it feels like there's way too many projectiles for a first level, making it very daunting to new players.
I feel like reducing the amount of projectiles and spreading out the three mechanics across the field for a full on applied tutorial would take the game to a whole new level and make it very accessible to all players :D
Of course, I completely understand you weren't able to get this done because of the circumstances, and there's no problem with that! You did the best you can. :D Consider this feedback as just a suggestion for some things to tackle should you choose to do more work on this after the jam :)
Once again, congratulations on finishing the jam despite your team's circumstances! Best of luck in future projects!
-Sasha