Nothing to do with the early 1970s sci-fi TV show Timeslip, is this Contra clone with a time travel theme an all time classic or just a slip up? More like the latter I'm afraid.
I do like the graphics and the sound is great with satisfying sound effects and good music. I wanted to like this game, but the extreme slow pace, stiff controls and the fact you need maximum weapon power to stand a chance against the difficult bosses who take ages to destroy meant I didn't enjoy this very much. It had potential but bad design will undermine your enjoyment of this.
The game over screen is wonderfully creepy though, declaring that as a result of your mission's failure you were never born...