You're being fooled by the graphics.
HenryG himself says it is 80% like CSGO. Do you know more about CS than a former pro turned caster?
-Similar movement (will have bhopping and strafejumping), a little bit slower, more akin to 1.6
-Utility: nades, smokes,flashes
-Bomb defusal mode
-weapon mechanics like CSGO, the sniper in the game is a direct ripoff of the awp, every gun has a different spraypattern
-TTK similar to CSGO
-Map design similar to CSGO (confirmed by HenryG), lanes, chokepoints, bombsites
-Has Volcano leading a lot of the game design and map design
-Economy and buy system like CSGO
Ults are said to not be overpowered and used only 2-3 times per match, they aren't guaranteed kills but more like advanced utility apparently.
Apart from having ults - which are said to function extremely different - how is this game similar to Overwatch?
TF2 would only be similar graphics-wise, apart from that: absolutely 0 comparison