Umm...yeah, something is certainly wrong.
FYI, the text object is pretty demanding (I know that sounds bizarre, but it's true). If you are updating it every tick, use a spritefont instead. From the man himself (search for 'text'):
https://www.scirra.com/manual/134/performance-tips
What about trying a real game with an exporter? Have you tried a test export of space blaster? Throw an fps/cpu meter on it (remember, use a spritefont) and export it. You could also print out the renderer; if it says canvas2D, then something is amiss.
For comparison, I have a much lower-end device -- LG Ultimate 2, Snap 205 1.2ghz, Adreno 305 -- and get very playable framerates in space blaster, even at it's most intense. My current project is using a couple webGL shaders and up to 50 onscreen objects, and hits 60fps consistently.
Also, I'm not seeing a great deal of difference between CocoonJS and crosswalk, but that may just be my projects.
Chrome could be causing a problem too...I haven't tested Chrome mobile extensively, but on desktop v38 had poor rendering performance that led to unstable framerates and 'janking'. This may have affected mobile as well.