A great simple game
One of the best things about any game is the gameplay, of course. And you can ensure good gameplay with... VARIETY! From the very moment your game loads and gives us the option of starting out with two types of cells with different evolving paths, strengths, and weaknesses... you're starting off well. Now, we get to the control scheme... arrows, spacebar, control... and we're off.
Digesting proteins... hunting for chunks of 4 or 5 or more little circles so as to not waste time with the little tiny ones... there's a lot of immediate fun to be had. It's been several weeks since I played much, but the replay value is there. The upgrades between levels, the clouds you have to avoid lest you wish your cells to die... and all the stuff flying around by the time you get pretty good and pretty far through the levels. It's all good. Warning to all, though: BEWARE VIRAL INFECTION!
The only thing I'd say needs much improvement is the lack of colour and visual variety. Sure, you've got your proteins, carbs, the little white and gray background blops... but for the most part it's a green sea with the little cells lost in its vast sameness. But I love green, personally, so at least it's a good choice for a drab colourscheme. #;-}>
A good, fun game... I wish you well in future game-making endeavours.