The big beast in the beginning is not verifiably sentient, so does not count for a kill. Also, the space battle afterward is all drones. The encounter between Rocket and the Ravagers up until 39:45 does not contain any verifiable kills as the dart launcher has unknown contents. It could just be knock out, the gravity adjustments similarly cannot be confirmed to kill as we don’t know the durability of the targets or the gravitational levels of the planet. He electrifies a group, but again this could just be a stun.
39:45 One Ravagers shoots another
48:44 Ravager ejected into space where we see 20 others that shared his fate and we see another sent right after the cut to space (22)
1:06:16 This is where Yondu activates his arrow on the ship and kills 26 in the first phase before the camera cut to the multi level part of the ship
1:07:29 This section is the multi level only and occurs over 3 camera angles. In the first angle Yondu kills 44 ravagers, in the second which has no overlap from the first he gets another 8 and in the third which does have overlap from the second as evidenced by the clearly blue skinned ravager, he kills another 21 totaling 73 for this section
1:08:00 Groot kills his tormentor
1:08:20 Starts the control room section of Yondu and Rocket slaughter which is incredibly difficult to count as there are many angles and screens to monitor, but here we go before the first cut they get 25, second camera cut nets them another 10, and they get 33 from the top down section totaling 68 for this part.
1:10:28 Tazerface explodes
There are points in the following sections where there are bystanders shown fairly close to the blue goo, but it does not overtake them on screen and due to the uneven speed at which the goo moves it is not a reliably confirmed kill.
1:49:55 blue goo kills 22
1:50:06 Five die on Xandar and then as the goo expands it kills approximately 84 more. It is difficult to tell because of the speed of video but this is what it appears with pausing and slow motion
1:50:22 Four aliens die to the goo
1:56:50 Ego dies
1:58:35 Yondu dies
Total: 299
Found this JoBlo kill count that comes in at 211. I have several differences to this count as they count all kills regardless of stature (like bugs and the big monster at the beginning). They also miss several kills throughout and understandably are unable to count the goo kills.
Carnage counts comes in at 298 which is remarkably close to my count. There are some differences in what we count as they count all creatures like JoBlo did as well as counting the electric stunning of some of the ravagers and some sort of implied blue goo kills. It also looks like they missed several blue goo kills.
Lastly this kill count is also close to my count at 289. Similar in differences to the two above, they also count several implied kills in the Yondu scene while missing others elsewhere.