It runs but with lots of delay, and i get the resolution message '1280 x 720' at the beginning.
Why is such the large resolution needed ? a lot of people will struggle to run it.
I honestly don't think it would run considerably faster for you if the game used a resolution of 1024x768 for example.
It's more an issue of a plethora of effects which are applied to a fair amount of sprites I would imagine. Also there are some unnecessarily big textures in the game, which might cause problems with weaker cards. Regarding that point I can (and will) improve.
One big performance issue that persisted even on newer systems is a short freeze that might happen when you manage to destroy many skulls at once. This is because the destroying effect will eventually force Construct to create 640 or more sprites at once, depending on the situation.
A big design flaw on my part of course, but I already cut it down to about 75% less sprites, while the effect itself still looks about the same. My own testing so far indicates that now those freezes are gone.
So there will be some performance improvements in the (hopefully) final test release 3. I can't promise it will make it run much smoother for you chrisbrobs, but I'm sure hoping it'll help some!