The yellow units buff the player with damage. The blue diamond unit should just be the other order of merging the base units. The rank of the units "shouldn't" matter but the bug I mentioned on the main page effects the merging process, so it might only be possible to get the blue diamond with the original rank one units. I'll be uploading a fix after the jam if you're interested in playing again :D

Thanks for the feedback. Was struggling for time at the end. It does indeed need a lot of balancing.

Thanks! Thats a tough lesson I learnt on the last jam. My game was so obscure nobody could understand it :P