I got a single-player test run in, and am very impressed at the foundation here!

1) The nice retro 8-bit/pixelized look of the core is fantastic.  On all units, really, but the core was just all around impressive. :-)
2) I like that the resources require doing more than turtling in and building up to be effective--you have to engage.
3) The fact you've got this done in just a couple weeks is massively impressive in and of itself.

As for suggestive feedback... I would love to see the overall game speed cranked up about... oh 50-75% maybe?  Right now it's seems you're going more for what I consider a micro RTS (meaning the battles are small scale with a focus on individual units--think Command & Conquer), versus a macro RTS (where it's more focusing on a large scale, and you're sending mobs of units and just concerned about army movements as a whole--a la Supreme Commander).  This is completely personal preference, but I think micro RTS need to be faster paced to really get a firm footing in the intense, small scale battles where each unit matters and you have to react **NOW** to win.  

That was a massive task for a game jam, so well done on getting it that far.  I'd need to play a real opponent to give you some proper feedback but here's some things I noticed in a single player wander around the map

1. The Core has a longer reach than the NPCs, so you can pick them off one at a time without ever alerting them or taking damage.
2. Money seems to come in really slowly so building your first few units seem to take ages. 

Definitely keep working on it though and let me know when you're free for a game!