7.66 avg 17 episodes 7.9 → 7.6 52 min avg
| # | Title | Rating | Votes |
|---|---|---|---|
| 1 | Beachhead | 7.9 | 459 |
| 2 | The Experiment | 7.7 | 344 |
| 3 | The Mutation | 7.6 | 342 |
| 4 | The Leeches | 7.5 | 307 |
| 5 | Genesis | 7.5 | 297 |
| 6 | Vikor | 7.7 | 305 |
| 7 | Nightmare | 7.3 | 283 |
| 8 | Doomsday Minus One | 7.6 | 290 |
| 9 | Quantity: Unknown | 7.7 | 284 |
| 10 | The Innocent | 8.3 | 326 |
| 11 | The Ivy Curtain | 7.8 | 268 |
| 12 | The Betrayed | 7.2 | 253 |
| 13 | Storm | 7.5 | 263 |
| 14 | Panic | 7.6 | 250 |
| 15 | Moonshot | 7.8 | 264 |
| 16 | Wall of Crystal | 7.9 | 244 |
| 17 | The Condemned | 7.6 | 233 |
7.73 avg 26 episodes 7.8 → 7.5 52 min avg
| # | Title | Rating | Votes |
|---|---|---|---|
| 1 | Condition: Red | 7.8 | 246 |
| 2 | The Saucer | 7.9 | 236 |
| 3 | The Watchers | 7.6 | 216 |
| 4 | Valley of the Shadow | 8.1 | 266 |
| 5 | The Enemy | 7.9 | 236 |
| 6 | The Trial | 7.8 | 242 |
| 7 | The Spores | 8.3 | 291 |
| 8 | Dark Outpost | 7.7 | 249 |
| 9 | Summit Meeting: Part I | 7.8 | 217 |
| 10 | Summit Meeting: Part II | 8.0 | 213 |
| 11 | The Prophet | 7.1 | 210 |
| 12 | Labyrinth | 7.8 | 212 |
| 13 | The Captive | 7.6 | 215 |
| 14 | The Believers | 7.7 | 222 |
| 15 | The Ransom | 7.8 | 213 |
| 16 | Task Force | 7.4 | 200 |
| 17 | The Possessed | 7.3 | 210 |
| 18 | Counter-Attack | 7.8 | 213 |
| 19 | The Pit | 7.6 | 200 |
| 20 | The Organization | 7.8 | 195 |
| 21 | The Peacemaker | 7.9 | 211 |
| 22 | The Vise | 7.7 | 201 |
| 23 | The Miracle | 7.4 | 213 |
| 24 | The Life Seekers | 8.0 | 215 |
| 25 | The Pursued | 7.8 | 214 |
| 26 | Inquisition | 7.5 | 210 |
