While I assume that a lot of this is due to Alpha status, disabling body parts in its current form suffer from issues, that impact gameplay and immersion.
Disabling arms beats everything. Soliders and crabs can both perform reasonably well with a disabled torso or their heads crippled, but shoot their arm and they become useless.
Getting your arm disabled or your weapon blown off isn’t particularly skill dependent. This means everytime your soldiers take a shot, there is a chance they’ll get crippled. While this isn’t unrealistic in itself, it may limit tactical options in the long term, minimizing the risk of getting your soldier incapacitated by a lucky shot will be a simple risk/reward matter.
Shields. While there are simply too many in the Alpha, I assume that enemy variety in the finished product will alleviate some of these issues (shielded enemies are often “elite” ones, mixed in with the regular mooks, since fighting them is usually time consuming). That said, shields are a tad too powerful atm, especially on shooty crab men that really don’t have many weak points.
Speaking of weak points it’s generally better to circle the enemy clockwise because that’s how you bypass the shied and get to the exposed weapon. Are there plans to introduce left handed (clawed?) crab men that hod their shields with their right “arm” to offer variation?