You can play the game without installing Impulse but you will not get any patches/updates from the origional boxed version. So, basically if you want to play the most recent version of Elemental you'll HAVE to install Impulse and USE IT to get your patches/updates.
It's really a no brainer as it isn't intrusive like a Steam client. It's just a protection service from piracy nothing more really, but, you can use it as a storage device for all your games you buy from Stardock. Once you've gotten your update you can even DELETE it from your hard drive but you'll have to REINSTALL it if you want another patch/update for your game(s).
And it's another useless program running in background which uses my computer's power.
Also THIS ^ is WRONG/INCORRECT as you can go into your MSconfig and uncheck the box that allows Impulse to start on bootup (as well as many more things in that Msconfig window) and it will not startup until you USE it for a PATCH/UPDATE. Then all you need to do after the patch update is bring up your TASK MANAGER and click on IMPULSE.exe and END PROCESS....wow that's soooooooo frickin hard to stop a program from running and gain power/memory back.
I have Impulse, Steam, Gamersgate, GoG and Digital River and NONE of these startup when I boot my computer because it's so simple to shut them off. So just because you're an igmo and don't know how to use your precious computer features then having all that power is pretty useless to you anyway.